Abstract: In this paper, numerical simulation on the deposition of 0.5-10 μm aerosol particle was performed by the program based on C++. The effect of coagulation and thermophoresis on deposition and their coupling relationship were studied. The results show that the effect of coagulation can be ignored when the aerosol particle number concentration is less than 10¹² m^-3, while the effect should be taken into consideration when the aerosol particle number concentration is 10¹⁴ m^-3. The deposition velocity of aerosol particle while considering coagulation is larger than that without coagulation. The deposition velocity is increased by 37.2% for 10 μm particle while considering coagulation when the temperature gradient is 3 000 K/m. The ratio of 0.5 μm particle deposition velocity (temperature gradient=3 000 K/m) to gravitational deposition velocity is 5.96 when neglecting coagulation. But the ratio decreases to 4.41 while considering coagulation when the aerosol particle number concentration is 10¹⁴ m^-3. The coagulation and thermophoresis interact with each other, but in general, coagulation and thermophoresis could enhance the deposition of aerosol particle, which speeds up the loss of aerosol particle.