To explore the psychological and educational conditions for developing self-efficacy skills by examining the impact of self-efficacy on second-language written instruction, we are looking for teaching methods and multidimensional assessment opportunities suitable for second-language written instruction. This study uses the Chinese English Essay Scale and Test as a tool to collect data, evaluate teachers, peers, and students' self-assessment of essays, and to examine the written self-efficacy of high school students in a second language, as well as the self-efficacy of high school students. There is a correlation between English language proficiency, teacher grades, student self-esteem, and peer grades. The results of the study show that: high school students' self-esteem when writing texts in English is usually at an average level; There are significant differences and strong correlations in high school students' grades and their low self-esteem written grades; there are significant differences in peer assessment, student self-assessment, and teacher assessment. A strong correlation shows that students' peer assessment and self-assessment coincide with the teacher's assessment and are trustworthy, which indicates the possibility and necessity of introducing peer assessment and student self-assessment when teaching writing in English.