Aims: To evaluate the effect of different colour mulches on Water use efficiency under protected cultivation a field experiment was carried out during April–June 2021 in Cucumber (Cucumis sativus). Study Design: Split plot design statistical design. Place and Duration of Study: Department of Soil and Water Conservation Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, between April to June 2021. Methodology: Different coloured Plastic mulches (black-M1, silver-M2, yellow-M3, red-M4, white-M5) and no cover M6 (control) with different irrigation levels (I1-100% PE, I2-75% PE and I3-50% PE) was adopted with split plot design. Results: The observed data revealed that using mulches decreased irrigation requirements of cucumber crop with comparing to no cover (without mulch). The data shows that Black Mulch M1 with I3-50%PE recorded the highest values of WUE (31.30 kg/m3) followed by White Mulch M5 with I3-50% PE (30.03kg/m3). Conclusion: Increasing irrigation level up to I2-75% improved yield with different coloured plastic mulch treatments, while the yield decreased with increasing irrigation level to I1-100%PE. Though using 50% PE with black plastic mulch increased WUE compared to using 75% PE or 100% PE without plastic mulch (control).