Abstract: It is inevitable to come into being friction in plastic working of metal plate. In order to detect the frictions of metal plastic deform by use of the acoustic emission technique, this paper studied the character of the acoustic emission produced in uniaxial tension and dynamic friction, the relative movement speed is 100mm/min, the stress is 7.5kg, of the steel SPCC. These two signals were compared and analyzed by use of the analysis method of relational parameters. The experimental results showed that (at the same detecting condition): ① the differences of the amplitude of the AE signal produced by tensile and dynamic friction are tiny; ② the value of energy of the AE signal produced by dynamic friction was more than the energy of the tensile test at the condition of the same amplitude, however, the ring count of the dynamic friction was less than the ring count of the tensile test; ③ the duration of acoustic emission signals in dynamic friction process was in the range from very low to the 8 000 μs; while the duration was less than 5 800 μs of acoustic emission signals in tensile process, and it was only at the time close to crack or fracture that acoustic emission signals had a higher duration.