Recently, the application of intelligent reflecting sur-face in wireless communications has attracted considerable attention. In this paper, the precoding of IRS-aided multiuser multiple-input single-output systems with one-bit digital analog converter at base station and discrete reflecting phase shifter at IRS is studied. The non-linear one-bit precoding and discrete phase are optimized jointly to minimize the mean square error. To solve this optimization, the alternate minimization strategy is employed to optimize precoding vector and discrete phase alternately. Moreover, the optimization for both constant-modulus phase-shift-keying (PSK) and general quadrature amplitude modulation (QAM) are considered. Concretely, the alternating direction method of multipliers algorithm and coordinate descent method (CDM) are utilized to acquire the one-bit precoding vector for PSK and QAM, respectively. In both PSK and QAM, CDM are employed to acquire the discrete phase optimization. Finally, computer simulations are given to demonstrate the effectiveness of proposed method.