  In last decades, legal case search has received more and more attention.
Legal practitioners need to work or enhance their efficiency by means of class
case search. In the process of searching, legal practitioners often need the
search results under several different causes of cases as reference. However,
existing work tends to focus on the relevance of the judgments themselves,
without considering the connection between the causes of action. Several
well-established diversity search techniques already exist in open-field search
efforts. However, these techniques do not take into account the specificity of
legal search scenarios, e.g., the subtopic may not be independent of each
other, but somehow connected. Therefore, we construct a diversity legal
retrieval model. This model takes into account both diversity and relevance,
and is well adapted to this scenario. At the same time, considering the lack of
dataset with diversity labels, we constructed a diversity legal retrieval
dataset and obtained labels by manual labeling. experiments confirmed that our
model is effective.
