Abstract: A new cylindrical-lens spatial filter is proposed to solve the blocking pinhole problem of a spatial filter. Compared with the conventional spherical-lens spatial filter, the new filter is constituted with cylindrical lens and slit. The transmission characteristics of high power laser beam in the new cylindrical-lens spatial filter are simulated using linear transfer theory. The results show that the area of the focal spot of the new filter is bigger than that of the conventional spherical-lens spatial filter, and the power density of the focal spot is smaller, while the filtering effect and near field uniformity keep the same. The new filter can effectively inhibit the blocking effect of the filtering pinhole. At the same time, the new filter can also improve the overall price of the laser device by shortening the focal length of lens. The new cylindrical-lens spatial filter to replace the conventional spherical-lens spatial filter is feasible.