The invention discloses a biomass-solar thermal chemical utilization system capable of realizing multi-product output. The system comprises a slot-type medium temperature solar pyrolysis absorption reactor, a coke separator, a waste heat recoverer, a tar condensation purifier, a high-temperature solar fluidized bed gasification reactor, an oil storage tank, a cyclone separator, a heliostats field and a hyperboloid reflector. By the aid of the system, high-temperature concentrating solar power is utilized to drive biomass to be subjected to pyrolysis and gasification reaction sequentially and independently according to the principle of 'parallel temperature', medium-temperature thermal energy at the temperature below 450 DEG C obtained by a parabolic slot-type equal line-focusing solar thermal collection device is utilized fully to drive the biomass to be subjected to pyrolytic reaction, carbon residue, tar and the like generated by reaction are subjected to gasification by utilizing high-temperature thermal energy at the temperature over 800 DEG C generated by a high-temperature solar concentrating thermal collection device, the concentrating and thermal collection process of the system is optimized, gasification efficiency of the biomass is improved, and tar content in gasification syngas is lowered.