In　this　paper,　based　on　the　forms　and　structures　of　Wronskian　solutions　to　soliton　equations,　a　Wronskian　form　expansion　method　is　presented　to　find　a　new　class　of　interaction　solutions　to　the　Kadomtsev-Petviashvili　equation.　One　characteristic　of　the　method　is　that　Wronskian　entries　do　not　satisfy　linear　partial　differential　equation.