This book aims to systematically elucidate the chemical and molecular mechanisms of life’s origins, focusing on the evolutionary processes in deep-sea hydrothermal vent environments—from inorganic small molecules to self-replicating RNA and ultimately to dividing protocells. By integrating the latest research in chemical evolution, molecular dynamics, and environmental feedback, we seek to address core questions in life’s origins: How do hydrothermal vents catalyze rapid chemical reactions? How does self-replicating RNA emerge from random molecular collisions? How does RNA complexity increase through mutation and selection? How does protocell division arise to lay the foundation for biological evolution? Beyond summarizing these mechanisms, the book attempts to construct a logically coherent theoretical framework to explore the dominant role of hydrothermal vents in life’s origins. The book targets academic readers, including scholars and graduate students in origin-of-life studies, chemical evolution, and molecular biology, while also providing accessible content for popular science readers interested in life’s origins. Through clear narration and rigorous analysis, we aim to provide new support for the RNA World hypothesis and offer theoretical insights for astrobiology (e.g., the search for extraterrestrial life) and synthetic biology (e.g., designing artificial life). Additionally, the book emphasizes quantitative approaches, using mathematical modeling and simulated data to reveal the inevitability of life’s origins, moving beyond traditional qualitative descriptions. The book comprises eight chapters, progressing logically from environmental context to molecular mechanisms and from simplicity to complexity. Chapter 1 introduces the physicochemical conditions and geological evidence of deep-sea hydrothermal vents as the stage for life’s origins, establishing the environmental foundation. Chapter 2 explores chemical evolution from inorganic to organic molecules, analyzing the efficient catalytic mechanisms of hydrothermal vents. Chapter 3 focuses on the formation of self-replicating RNA, revealing how it transitions from random collisions to an active proliferation system. Chapter 4 examines the minimal unit of RNA self-replication, analyzing the optimization of sequence length and mutation rates. Chapter 5 proposes a feedback-driven model for RNA length evolution, elucidating how complexity increases through environmental selection. Chapter 6, from a molecular dynamics perspective, describes the evolutionary pathway from self-replicating RNA to dividing protocells. Chapter 7 synthesizes the synergistic interactions and limitations of these mechanisms, while Chapter 8 summarizes key findings and outlines future research directions. Appendices provide mathematical models, figures, and a glossary to facilitate deeper understanding. Through this structure, the book aims to offer readers a comprehensive and in-depth perspective on life’s origins, from the chemical environment of hydrothermal vents to the biological functions of protocells, revealing the magnificent journey of life’s emergence on Earth. We hope this book not only contributes new theoretical insights to academia but also inspires public interest and reflection on the eternal question of life’s origins.