The invention discloses a device and a method for generating a spectrum amplitude code mark and measuring a bit error rate. The device for generating the spectrum amplitude code mark and measuring the bit error rate provided by the invention, includes a multi-wavelength laser device array module, a mark encoder, a combiner, a digital control signal generating module, a mark identifying module and a bit error rate tester. According to the device and method for generating the spectrum amplitude code mark and measuring the bit error rate provided by the invention, the spectrum amplitude code mark with randomly adjustable marking speed and encoding sequence and controlled by a random digital signal generator can be generated, the flexibility of encoding and marking speeds of the spectrum amplitude code mark switching system is greatly improved, meanwhile the measurement of the bit error rate characteristic of the spectrum amplitude code mark can be achieved; the system is simple in structure, easy to implement, and very strong in actual operability.