In the research fields of humanity and social science, despite the lengthy and rich dialogue on the issue of 'value neutrality', many questions pertaining its meaning, feasibility and desirability remain, by and large, unresolved. This article seeks to accomplish a systematic analysis basing on some insight of predecessors of this area. Analyzing separately 'what is and what ought to be', 'value neutrality in the empirical study', 'value neutrality in the logical inference', and 'the liberal neutrality', I hope this article can clarify the view each made in debate, and can offer some temporary answers for these questions.