Background: Preparing and maintaining the original shape in conjunction with its disinfection, exclusive of any procedural error is mandatory in endodontic treatment. Nickel-titanium instruments are much more flexible than conventional stainless steel files combined with superior cutting efficiency. The purposes of this study were to measure and compare the canal transportation, centering ratio at different levels of simulated curved canals of the endodontic training resin blocks, which were instrumented by using of 4 Niti rotary endodontic systems’ Protaper Next, OneShape, Protaper Gold, and TwoShape. Material and Methods: Total 60 resin blocks were randomly divided into 4 groups of 15 canals each; the 1st group was prepared with Protaper Next instruments, the 2nd was prepared with OneShape, the 3rd was prepared with Protaper Gold instruments, and the 4th was prepared with the TwoShape. All were prepared for the size of 25. Removal of material was measured at 5 different levels: at the canal orifice, halfway to the orifice in the straight sections; the beginning of the curve; the crest of the curve; the endpoint. Pre and post-operative photos of the simulated canals were taken in a standardized technique. An assessment of changes has been determined using Photoshop and Digimizer Software. The data were analyzed statistically using Shapiro-Wilk, ANOVA by SPSS software version 21. Results: Regarding the canal transportation, the direction of transportation of rotary NiTi instruments was usually towards the inner aspect at middle parts of the canal, towards the outer aspect of the curve at the apex of the curve and the end of preparation. Conclusion: The TwoShape produced the least amount of canal transportation and preserved the original curvature of the canal more than the other systems evaluated in this study.