All I am trying to do is creating a quad in world coordinate and put a 64*64 texture on. I disable the lighting and enable the alpha.

Here is part of the codes, really have no idea what the problem is.

float Rot = 0.0f;
struct QUAD 
{
	D3DXVECTOR4	 Pos;
	//D3DXVECTOR4	 Nor;
	D3DXVECTOR2  TexCoord;

	static const DWORD  FVF;
};
const DWORD QUAD::FVF = D3DFVF_XYZ | D3DFVF_TEX1;//RHW D3DFVF_NORMAL

IDirect3DVertexBuffer9*	g_pVB;
IDirect3DIndexBuffer9* g_pIB;
void LoadTexture(IDirect3DDevice9* pd3dDevice)
{
	hr = D3DXCreateTextureFromFile(pd3dDevice,L"LidTexTest.png",&WholeTex);
	WholeTex->GetSurfaceLevel(0,&WholeTexSur);

}
void CreateQuad(IDirect3DDevice9* pd3dDevice)
{
	hr = pd3dDevice->CreateVertexBuffer(
		4 * sizeof(QUAD),
		D3DUSAGE_WRITEONLY,
		QUAD::FVF,
		D3DPOOL_MANAGED, 
		&g_pVB,
		0);

	QUAD temp[4];
	temp[0].Pos = D3DXVECTOR4(-0.5,0.5,0,1);
	temp[1].Pos = D3DXVECTOR4( 0.5,0.5,0,1);
	temp[2].Pos = D3DXVECTOR4(-0.5,-0.5,0,1);
	temp[3].Pos = D3DXVECTOR4( 0.5,-0.5,0,1);

	temp[0].TexCoord = D3DXVECTOR2(0.0f,0.0f);
	temp[1].TexCoord = D3DXVECTOR2(1.0f,0.0f);
	temp[2].TexCoord = D3DXVECTOR2(0.0f,1.0f);
	temp[3].TexCoord = D3DXVECTOR2(1.0f,1.0f);
	
	VOID* lpVertices;
	g_pVB->Lock( 0, sizeof(temp), (void**)&lpVertices, 0 );
	memcpy( lpVertices, temp, sizeof(temp) );
	g_pVB->Unlock();

	int iIQuantity = 6;
	int Index[6];

	Index[0] = 0;
	Index[1] = 1;
	Index[2] = 2;
	Index[3] = 2;
	Index[4] = 1;
	Index[5] = 3;
	
	unsigned int uiBufferLength = (unsigned int)(iIQuantity*sizeof(int));
	pd3dDevice->CreateIndexBuffer(uiBufferLength,
		0,D3DFMT_INDEX32,D3DPOOL_MANAGED,&g_pIB,0);

	void* pbIndices;
	g_pIB->Lock(0,uiBufferLength,&pbIndices,0);

	memcpy( pbIndices, Index, iIQuantity*sizeof(int) );	

	g_pIB->Unlock();
}
HRESULT CALLBACK OnD3D9CreateDevice( IDirect3DDevice9* pd3dDevice, const D3DSURFACE_DESC* pBackBufferSurfaceDesc,
                                     void* pUserContext )
{
	SetupCamera(pd3dDevice);
	LoadTexture(pd3dDevice);
	CreateQuad(pd3dDevice);
    return S_OK;
}

void CALLBACK OnD3D9FrameRender( IDirect3DDevice9* pd3dDevice, double fTime, float fElapsedTime, void* pUserContext )
{
    HRESULT hr;

    // Clear the render target and the zbuffer 
    V( pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, D3DCOLOR_ARGB( 0, 45, 50, 170 ), 1.0f, 0 ) );
	pd3dDevice->SetRenderState( D3DRS_LIGHTING, false );
	pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
	pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
	pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
	pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
	
    // Render the scene
    if( SUCCEEDED( pd3dDevice->BeginScene() ) )
    {
		Rot = Rot + 0.00;
		D3DXMATRIX matTemp;
		D3DXMATRIX m_matWorld;
		D3DXMatrixIdentity(&matTemp);
		D3DXMatrixIdentity(&m_matWorld);

		D3DXMatrixRotationY(&matTemp, Rot);
		D3DXMatrixMultiply(&m_matWorld,&m_matWorld,&matTemp);

		D3DXMatrixMultiply(&m_matWorld,&m_matWorld,&matTemp);

		pd3dDevice->SetTransform( D3DTS_WORLD, &m_matWorld);

		pd3dDevice->SetFVF(QUAD::FVF);
		pd3dDevice->SetTexture(0,WholeTex);
		pd3dDevice->SetStreamSource(0, g_pVB, 0, sizeof(QUAD));
		hr = pd3dDevice->SetIndices(g_pIB);
		hr = pd3dDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,0,0,4,0,2);
		pd3dDevice->SetTexture(0,NULL);

        V( pd3dDevice->EndScene() );
    }
}

Many thanks

oh the texture is fine, because I can render it with a quad on screen coordinate, just when I use world coordinate to describe the quad, the texture go crazy.