The three dimensional numerical solution for differential equation of motion of sparse solid particles in flow fields is derived. Taking free sedimentation of solid particles as an example, using dimensionless differential equation, the movement rule of solid particles in water and air is numerically analyzed. The contribution of Basset force on solid particles in different density flow fields is paid much attention to. The results show that the Basset force and drag force are in the same magnitude when solid particles move in water; the effect of Basset force can be neglected when solid particles move in the air; and the Basset force should be considered when river water source heat pump and the flow of silt particles are studied.