Two-dimensional strip is a common flow control method to accelerate flow transition. The wavefront distortion resulting from hypersonic boundary layer has been investigated in virtue of theoretical analysis and wind tunnel experiments. Wavefront measurement system is used to measure the wavefront distortion of hyper-sonic boundary flow, and compare the distribution of flow wavefront with and without strip. The results prove that high-precision wavefront measurement system can present not only wavefront but also density distribution be-fore the flow transition of boundary layer. In addition, the experimental results show that the wavefront distortion increases quickly when the flow is obviously unstable. Finally, comparing the distribution of wavefront induced by strip with the corresponding data without strip, we find that the mean wavefront, root mean square and peak-valley value of wavefront with strip are much larger than that without strip.