High-performance electrode materials are crucial for enhancing the performance of supercapacitors. Among various candidates, pseudo-capacitive SnS2 is a promising one due to its high specific capacitance, earth-abundance, nontoxicity as well as low-cost. However, its actual electrochemical performance is restricted owing to the poor intrinsic conductivity and current fabrication processes on improving the conductivity are usually complicated. In this study, based on first-principles calculations, Pb doping is introduced to enhance the conductivity of SnS2. Pb-doped SnS2 nanosheets are synthesized via a simple one-step hydrothermal method. With trace Pb doping (Pbo.o1SnS2), an impressive 4-order-of-magnitude increase in conductivity was achieved compared to pristine SnS2. Furthermore, Pb-doped SnS2 nanosheets exhibit a superior mass-specific capacitance of 533.7 F g−1 at 50 mV s−1 and excellent long-term capacitance retention of 90.2 % over 100,000 cycles at 5 A g−1. This study presents a simple and effective approach to enhancing the supercapacitor performance of SnS2 and advances the practical applications of electrochemical energy storage devices based on 2D materials.