In　this　paper,　a　modified　floor　field　model　is　presented　to　study　crowd　dynamics　involving　individuals　with　disabilities　(i.e.　pedestrians　on　crutches,　seniors　with　sticks,　pedestrians　in　manual　wheelchairs　and　blind　pedestrians).　Multi-speed　characteristics,　overtaking　and　helping　behaviors　are　considered　in　our　model.　Through　simulations　in　unidirectional　pedestrian　flow　in　a　corridor,　it　is　observed　that　overtaking　behavior　has　a　positive　effect　on　pedestrian　flow　at　low　density.　Helping　behavior　can　significantly　improve　the　maximum　flow　rate　and　critical　density　of　a　system.　In　comparison　with　overtaking　behavior,　helping　behavior　is　more　beneficial　to　heterogeneous　crowd　movement,　when　density　is　higher　than　the　critical　density.　The　phenomenon　that　the　proportion　of　individuals　with　disabilities　has　a　negative　influence　on　crowd　movement　efficiency　is　reproduced.　It　is　hoped　that　this　study　will　enrich　movement　rules　and　modeling　approaches　for　individuals　with　disabilities,　and　be　helpful　in　crowd　management　and　evacuation　organization.