Objective： To reveal the compositions of betalains (BLs) from pitaya fruit and their distribution in different parts. Methods: Three types of pitaya fruits, red peel-red flesh (RR), red peel-white flesh (RW), and yellow peel-white flesh (YW), were selected. The screening and confirmation of BLs were performed by ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC QTOF-MS/MS). Results: A total of 19 components were identified, including betanin, phyllocactin, indicaxanthin, etc. Most components (14) were identified from the peel part of RR fruit, and secondly, 12 components from the flesh part of RR fruit and nine components from the peel part of RW fruit. Conclusion: Among the various pitaya fruits, RR fruit presented the most prosperous components, and the following were RW and YW fruit. BLs components are predominantly distributed in the red flesh and red peel parts. The white flesh and yellow peel parts were scarce of BLs components.