Abstract: Solanaceous vegetables (including tomato, eggplant, and pepper) are economically important vegetable crops worldwide. Their plant architecture traits are directly associated with yield potential, mechanization adaptability, and resource utilization efficiency, and have thus become a core focus of breeding and cultivation research. This paper systematically reviews the major research advances in this field in recent years, with emphasis on four aspects: influencing factors, molecular basis, high-throughput phenotyping technologies, and practical applications. Firstly, we comprehensively analyze the synergistic regulatory effects of endogenous hormones (e.g., gibberellins, auxins, cytokinins) and exogenous environmental factors (including light, temperature, water, fertilizers, and cultural practices such as pruning) on key plant architecture traits, such as plant height, branch number, and leaf morphology. Secondly, we summarize key genes identified in these three crops via genetic mapping strategies including bulked segregant analysis (BSA), genome-wide association study (GWAS), and map-based cloning—such as SlGID1a in tomato, CaSLR1 in pepper, and dwf in eggplant—and further generalize the hierarchical and interactive molecular regulatory networks centered on hormone signaling pathways. Thirdly, we evaluate the development of high-throughput phenotyping technologies, focusing on non-destructive, dynamic, and precise phenotyping acquisition methods based on machine vision, spectral sensing, and deep learning. Finally, we conclude the integrated applications of marker-assisted selection, CRISPR/Cas9-mediated gene editing, and intelligent environmental control systems in the creation of ideal plant architecture and efficient production practices. Future research should focus on decoding the complex gene-environment interaction mechanisms, developing low-cost and high-precision phenotyping platforms suitable for field conditions, and constructing multi-trait synergistic improvement breeding systems that balance yield, quality, and stress resistance. These efforts will provide theoretical support and technical pathways for the green and high-quality development of the solanaceous vegetable industry.