Abstract: In order to obtain single-order harmonics with adjustable wavelength, the method of adjusting and controlling the waveform of two-color field laser was used. Harmonic radiation was analyzed theoretically. The data of single-order harmonic enhancement ranging from the 182nd to 328th were obtained. The results show that, the enhancement of single-order harmonics comes from the folded region in short quantum path of harmonic radiation. Pulse width of the second control field has great influence on the folding region of harmonic radiation. This study provides new scheme for obtaining single-order harmonic pulses. It is helpful for the development of laser source.