Detection of buried trash in scattering media is a very important research project. Detection efficiency is influenced by several imaging parameters, such as incident light intensity, trash buried depth, medium refractivity, medium scattering coefficient and medium anisotropic factor. Firstly, current Monte Carlo algorithm is revised. Secondly, influential laws of those parameters are researched by simulating a great number of photons propagating in a scattering medium. The results indicate that light intensity, trash buried depth and medium refractivity greatly affect both reflection and transmission imaging results; and their influential laws are similar. Detection efficiency of reflection imaging can be improved by increasing light intensity, reducing trash buried depth or medium refractivity. Detection efficiency of transmission imaging can be improved by increasing light intensity, reducing medium refractivity and scattering coefficient, or increasing anisotropic factor. These conclusions have universal significance of guidance in the detection of buried trash in scattering media.