Radiative decay of $\eta^{\prime}$ in CLAS

We would present preliminary experimental results of the radiative decay of $\eta^{\prime}\rightarrow\pi^{+}\pi^{-}\gamma$ based on CLAS data collected during the photoproduction experiment $\gamma p\rightarrow p\eta^{\prime}$ for the center-of-mass energy from 1.96 to 2.72 $GeV$ at Jefferson Lab. The analysis is based on the highest statistics collected in this channel in comparison to other experiments reported so far. This analysis could provide an important test of the box anomaly, also accessible via the Primakoff reaction of $\pi^{-}\gamma^{*}\rightarrow\pi^{-}\pi^{0}$.