A method of photoacoustic (PA) tomography with the filtered back projection is proposed. For the PA signals of the source, real PA pressures are obtained by deconvoluting the impulse response of the transducer used for detecting the PA signals of samples. The optical absorption distributions of the samples are reconstructed using the filtered back projection with sufficient PA pressures in different directions. The data are filtered with SL (Slion-Line) filter before back projecting. Simulations and experiments were performed to compare the filtered back projection and the direct back projection. The results prove the filtered back projection method is valid for PA imaging. Combining this image method, the two-dimension PA images of four absorbers buried in 12 mm were reconstructed.