Limited-projection fluorescence molecular tomography (FMT) allows rapid reconstruction of three-dimensional distribution of fluorescent targets in animals through shorter data acquisition times. However, due to less projection data, the limited-projection FMT undergoes severe ill condition. In order to reduce the ill condition of FMT reconstruction and improve the reconstruction speed, we propose a reconstruction method for limited-projection FMT. Considering the characteristics of the sparse distribution of the target of FMT, this method combines with smoothed l0 norm and feasible region of prior information. A continuous function approximates the smoothed l0 norm, which improved the calculation speed. And the feasible region of the prior information improves the precision of the recovered results. The reconstruction results of digital mouse model show that the position error of the reconstructed image is less than 1 mm at 3, 6 and 9 excitation points and the reconstruction time is shortened, and the reconstruction time under the 3 excitation points is 8 s. The reconstruction result of physical phantom further verifies the feasibility of this method in practical FMT applications.