The primordial non-Gaussianity induces scale-dependent bias of the Hi with respect to the underlying dark matter, which exhibits features on the very large scale of the 21-cm power spectrum potentially observable with Hi intensity mapping observations. We forecast the prospective constraints on the four fundamental shapes of primordial non-Gaussianity (local, equilateral, orthogonal, and enfolded), with the current and future Hi intensity mapping experiments, BINGO, FAST, and SKA-I. With the current configuration of the experiments and assumed one-year observation time, we find that the SKA-I will provide tighter constraints on the local shape of primoridal non-Gaussianity than Planck. The results are (σfNLlocal,σfNLequil,σfNLorth,σfNLenfold)SKA-I=(0.54 ,86 ,25 ,43 ) , (σfNLlocal,σfNLequil,σfNLorth,σfNLenfold)BINGO=(17 ,100 ,128 ,164 ), (σfNLlocal,σfNLequil,σfNLorth,σfNLenfold)FAST=(9.5 ,44 ,75 ,94 ) . If the lower frequency band of FAST can be used, the constraint on local-type primordial non-Gaussianity will be σfNL̃1.62 which is better than Planck. In addition, if the observation time for FAST could be extended to two years, the constraint on the equilateral shape of primordial non-Gaussianity would be improved to σf NL̃32 . Similarly, if the observational time of SKA-I could be extended to two years, the constraint on local and orthogonal shapes could be improved to 0.43 and 20, respectively, achieving better constraints than Planck.