Heterophase junction (HPJ) and hole trapping was regarded as effective strategies to improve photogenerated carrier separation and photocatalytic performance. In this work, a TiO HPJ with tunable anatase/rutile ratio was in-situ grown on –OH terminated TiCT MXene for efficient photocatalytic hydrogen production via a simple hydrothermal route in the presence of HCl. The number of anatase/rutile phase junction and TiO/TiCT heterojunction could be readily regulated by HCl concentration and hydrothermal duration, respectively. The optimized photocatalyst exhibited few layers TiCT MXene embedded into TiO with an atomic scale interface, containing a large amount of rutile/anatase phase junction. The mass and surface area normalized hydrogen evolution reaction (HER) performance of A/R-TiO/TiCT-36–0.25 (0.2 wt% Pt) achieved 4672.0 μmol gh and 244.6 μmol h m, which were 3.76 and 9.8 times higher than those of commercial P25 (0.2 wt% Pt), respectively. Apparent quantum yield of 27.11% at 350 nm also obtained on the optimum photocatalyst. The surface chemical analysis showed that the ethylene glycol treated TiCT MXene adsorbed a large amount of –OH on the surface which enabled a low work function (Φ = 2.28 eV). Therefore, photo-generated carriers were separated at the anatase/rutile phase junction interface, and photo-generated holes on TiO valance band were trapped by TiCT (T = –OH), so that the photocatalyst had remarkable charge separation and photocatalytic HER efficiency. This study could shed light on the new approach to the rational design of high-efficiency MXene-based heterophase junction photocatalysts.