This book focuses on the basic physical process and chemical reaction of plasma spraying particle melting, flight and deposition. It introduces the basic scientific contents such as the basic characteristics and spraying principle of plasma arc, the interaction between spraying particles in flight section and plasma jet, the spreading and solidification behavior of single droplet and the performance test of flat particles, macro performance evaluation and quality optimization of coating. The typical applications of plasma spraying coating and the new developing direction of plasma spraying technology are summarized. This book will be helpful for the graduate students, researchers, as well as engineers in the field of plasma spray.