In non-uniformly heated natural convection systems, the net horizontal flow, namely thermal drift, can be induced by rationally configuring non-flat walls, thereby achieving convection control. The heat transfer process in volumetric solar collectors is mainly dominated by the thermal convection driven by non-uniform concentrated radiation. To explore the formation conditions of thermal drift in radiation-driven thermal convection systems and the influence laws of key control parameters, so as to provide a theoretical basis for the heat transfer control in volumetric solar collectors, numerical simulations were conducted using the finite volume method. It was found that in radiation-driven thermal convection systems, the formation of thermal drift is attributed to the net horizontal pressure component on the lower wall. When the phase difference between the non-flat lower wall and the non-uniform incident radiation is 0 or π, the net horizontal pressure component is close to 0, the flow function is symmetric, and no thermal drift occurs. In other phase difference cases, the net horizontal pressure component is not 0, resulting in thermal drift. In addition, the thermal drift intensity changes sinusoidally with the phase difference, increases with the increase of the amplitude of the lower wall and the amplitude of the incident radiation, and increases first and then decreases with the wave number of the lower wall and the fluid height. Within the Rayleigh number of 10³≤Ra≤10¹⁰, the thermal drift intensity increases with the increase of Ra, but the growth rate changes twice, from Ra to Ra^0.6, and then to Ra^0.37.