This paper studies the translation of scientific Japanese texts based on the theories of science translatology, and discusses the guiding role of its three key principles translation. In the meantime, specific translation strategies are analyzed with examples which feature scientific Japanese texts. It is found that: the principle of pragmatic value can increase the translation's acceptability in terms of culture, terminology, and expression; The principle of linguistic meaning emphasizes the acceptable content which convey the most complete scientific and technological knowledge in the source texts; The principle of expression aims at a better match between the expression in the target language and source language. In addition, the full translation strategy such as amplification, omission, conversion, splitting and combination can be applied to effectively improve the quality of scientific translation from Japanese into Chinese.