A single frequency Brillouin fiber laser is designed and developed wit hout using expensive instruments or complicated system.And the effects of fiber length and pump po wer of Brillouin ring laser on the performance are experimentally demonstrated.It can be found that the bandwidth of Brillouin rin g laser is gradually reduced and the conversion efficiency of the output light is firstly increased and then progr essively decreased with the decrease of fiber length.The single frequency Brillouin laser is obtained by optimizing the fiber length and pump power.The stability of the ring laser is achieved,and the fluctuation of bandwidth and center frequency is about 0.1MHz. Experimental results show that the single frequency Brillouin ring laser exhibit s high stability.