The theoretical model of QBER (Quantum Bit Error Rate) was established with POVM (Positive Operator Valued Measurement).PANDA fiber as an example was simulated based on the model.The research results show that under the same angle,bit error rate (BER) increases with increase of force amplitude; and BER increases with increase of angle,under the same force without the consideration of 0 and π/2.For normalized force less than 0.4 or the angle less than π/12,the BER could be lower than 5%.