In order to study the quantum effects in the liquid helium,we use path integral Monte Carlo(PIMC) method to simulate the liquid helium system.We calculate the number of atoms which permute with others,the pair-correlation function,the structure factor and the superfluid fraction on the platform of pimc++.Comparison between experiments and the results of pair-correlation and structure factor computed by PIMC manifests the precision of this method and the strength of this approach in simulating the microscopic arrangement of atoms in liquid helium.Below 4K,the number of atoms which permute with others increases as the temperature goes down,the quantum effects become more and more apparent.At about 2.17 K,the system will undergo a phase transition and turn into superfluid.The superfluid fraction will increase as the temperature goes down,and eventually equals to 1.Path integral Monte Carlo can simulate the structure of liquid helium with high precision and reflect the quantum effects of particle permutation and transition to the superfluid state.