The rate equations of all-fiber acousto-optic Q-switched lasers were solved under different initial boundary conditions by numerical simulation, and the distribution of upper-level population density along the doped fiber under forward pumping and backward pumping, and the relations between pulse energy, average power, pulse width, stored energy and pulse repetition rate, signal transmittance of the pump coupler, and pump power, were obtained. The simulation was analyzed from the viewpoint of the amplified spontaneous emission light, and an all-fiber Y3+b-doped acousto-optic Q-switched laser was employed experimentally to test the effect of pumping manners on the average power and pulse width. The results show that pumping manners significantly affect the performance of all-fiber acousto-optic Q-switched lasers under different pulse repetition rates, so the lasers should be forward pumped for better characteristics of output pulses under lower pulse repetition rate, and they should be backward pumped under higher pulse repetition rate.