The monolithic integration of a tunable V-coupled-cavity laser based on half-wave multimode interference reflector (MIR-VCL) with a travelling-wave Mach-Zehnder modulator (TW-MZM) on generic InP foundry platform is present in this paper. The formation mechanism of pi-coupling-phase difference and the contradiction among loss, optimal coupling phase difference and optimal coupling coefficients of half-wave coupler are analyzed. Single electrode tuning of 11 channels of about 7.3nm wavelength range is obtained, which is determined by the cavity length and the 10% cavity length difference. Among the whole wavelength tuning range, the side mode suppression ratios (SMSRs) are all above 35dB and the typical one is about 42dB. The Mach-Zehnder modulator with optimized travelling wave electrode is integrated with the MIR-VCL by two two-ports MIRs, which could provide optical feedback for laser and CW light for MZM in the meantime. The monolithic integrated transmitter on generic InP platform is free of complicated fabrication process of grating structure and has good potential for cost effective applications.