1. A method of generating an assistant feature executed by a computing system, comprising: providing a plurality of main features; selecting a first main feature from the main features; disposing a plurality of rule-based features around the first main feature; generating a model-based feature around the first main feature; and extracting an overlap Boolean feature from the rule-based features, wherein the overlap Boolean feature overlaps with the model-based feature in an overlap ratio up to a target value, the overlap Boolean feature serves as an assistant feature, and the assistant feature and the first main feature constitute a transfer feature.