【Objective】 The study aims to provide a theoretical basis for potato disease resistance breeding by investigating the characteristics of the potato defensin gene StPSK4 and conducting a functional analysis of its role in potato disease resistance. 【Methods】 The authors Utilized bioinformatics techniques for a systematic analysis of StPSK4, conducting transcriptome sequencing analysis to study the tissue-specific expression patterns of StPSK4 under biotic and abiotic stress conditions, assessing the plant innate immune responses and sensitivity to Pseudomonas syringae in StPSK4 overexpressing plants. 【Results】 The cDNA full length of the StPSK4 gene was 457 bp, encoding 100 amino acids; StPSK4 contains a signal peptide, with its tertiary structure mainly composed of α-helices and random coils; The C-terminus of PSK4 contains the defensin sequence YIYTQ; StPSK4 shared a high similarity of over 80% with Solanaceae crops; StPSK4 was highly expressed in potato sprouts and petioles, and showed strong responses to abiotic stresses such as high temperature, salt, P. syringae, and Phytophthora infestans. Transgenic potato plants overexpressing StPSK4 had been constructed and obtained. Overexpression of StPSK4 suppressed ROS burst in potato, defensed marker gene expression, and enhanced resistance to P. syringae. 【Conclusion】 StPSK4 was involved in potato stress response and suppressed potato's disease resistance function.