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Abstract. It is simulated that the photoacoustic effect in three-dimensional model to compare photoacoustic effect with attenuated different Gaussian radii distribution light sources by the finite element method (FEM). We motivate the enclosed photoacoustic cell at a range of frequencies and compare the results of the amplitude of acoustic pressure frequency curve, the distribution of acoustic pressure and the variation of temperature within the gas layer. IntroductionThe photoacoustic effect was found in 1880 by A.G.Bell [1], the famous telephone inventor. However, due to lack of light source of good performance and acoustic transducer of high sensitivity, the study of photoacoustic effect had been stagnant. At that time, the photoacoustic phenomenon in gases had been satisfactorily explained, but liquid and solid were not. With the advent of laser device and microphone, the photoacoustic effect get people's attention again. In 1976, the basic theory of photoacoustic effect in condensed matter was proposed by Rosencwaig and Gersho [2]: a periodically modulated laser beam is focused onto the material, and part or all of the absorbed light energy is transformed to heat through non-radiative de-excitation process. Owing to alternate expansion and contraction of gas layer adjacent to the solid surface, the photoacoustic signal which has the same frequency as the modulated frequency and amplitude, phase depending on the material characters is generated. This theory is known as the "RG" theory which is the basis of modern photoacoustic. From then on, many scholars have studied the theory of photoacoustic effect. McDonald and Wetsel [3] established the thermoelastic coupled equations and given the first order approximate solution. Hanping Hu [4,5] considered photoacoustic coupled equations of multilayer materials and derived the analytical solution. All of these sound is generated within the gas layer and detected by acoustic transducer in the surrounding gas, but Gu Liu [6] considered both heat and photoacoustic signal are generated and detected within the same solid or liquid. There are also some simulated research on gas photoacoustic cell [7,8]. But there are few discussion about comparison of three-dimensional photoacoustic cell with attenuated different Gaussian radii distribution light source using the finite element method(FEM).