Controlling　molecule　aggregation　in　polymer　films　is　one　of　the　key　factors　in　understanding　the　links　between　properties　and　structures　in　organic　semiconductors.　Here,　we　used　poly(3-hexylthiophene-2,5-diyl)　(P3HT)　as　the　model　system.　By　doping　the　insulating　polar　additive　poly　(ethylene　oxide)　(PEO)　into　P3HT　film　and　controlling　the　processing　methods,　we　achieved　the　side-to-side　H-aggregate　and　head-to-tail　J-aggregate　of　P3HT　molecules　with　different　extents　at　room　temperature.　We　have　demonstrated　that　the　solvent　solidification　rate　plays　an　important　role　in　the　controlling　of　molecule　aggregation,　which　finally　influenced　the　solid-state　phase　separation　in　the　film.　Furthermore,　based　on　a　series　of　spectroscopy　investigations,　we　quantified　the　electronic　spatial　coherence　in　different　aggregations　combined　with　the　modified　Franck-Condon　model.　Subsequently,　we　established　the　relationship　between　the　processing　method,　the　molecule　aggregation,　and　the　electronic　spatial　coherence.