Compared with single pile, the penetration effect of group piles is more complicated. XCC pile is a non-circular section special-shaped pile. However, little research has been made to investigate the penetration effect of the special-shaped pile. Based on the transparent soil test, the pile penetration test of XCC and circular group piles with equal section was carried out. The displacement field of the surrounding soil is obtained by particle image velocimetry technology. The displacement field results after the penetration of the first pile are compared and analyzed with the calculation results of the cavity expansion theory and the shallow strain path method, which verifies the reliability of the test. Experimental results show that obvious cumulative effect and shielding effect can be observed during the penetration of XCC and circular group piles. Finally, an empirical formula for predicting the shielding effect for XCC and circular piles under different penetration sequence was given.