Herein, we report a novel and effective strategy to prepare ternary PbCdS nanocrystals, where Cd2+ is successfully doped into PbS to form PbCdS via one step reaction. Moreover, the as-prepared PbCdS NCs are firstly applied in the hole transport layer of the inverted CH3NH3PbI3 solar cells. It is found that the well matched highest occupied molecular orbital (HOMO) energy levels of PbCdS NCs and CH3NH3PbI3 contribute to the enhanced charge extraction rate and boosted Voc. The inverted CH3NH3PbI3 solar cells based on PbCdS NCs as hole transport layer yield a peak power conversion efficiency up to 17.1% with average efficiency of 16.5%. Meanwhile, the as-prepared PbCdS NCs applied as anode material in the Li-ion batteries exhibit high capacity and excellent cyclability, indicating that PbCdS NCs can be a promising electrode material in Li-ion batteries as well.