To explore the relationships between parent-child relationship, loneliness, cyberbullying and cybervictimization behavior in junior high school students, 843 junior high school students anonymously completed the Parent-child Relationship Questionnaire,UCLA Loneliness Scale and Cyber-bullying Inventory. It was found that: 1) good parent-child relationship negatively predicted loneliness, cyberbullying and cybervictimization, while loneliness positively predict cyberbullying and cybervictimization; 2) there were different modes of loneliness in parent-child relationship influencing cyberbullying and cybervictimization in junior high school students, that is, loneliness played a complete mediating role in parent-child relationship influencing cyberbullying behavior, and it played a part of imediating role in the influence of parent-child relationship on cybervictimization.