This　paper　considers　the　problem　of　the　formation　control　for　multiple　underactuated　quadrotor　UAVs　without　linear　velocity　measurements.　The　objective　of　this　paper　is　expected　to　realize　smooth　formation　performances　for　a　quadrotor　group.　A　distributed　formation　controller　is　designed　directly　using　rotation　matrices　to　obviate　the　singularities　associated　with　the　Euler-angles　or　the　ambiguity　of　quaternions.　A　two-step　procedure　is　adopted　for　the　control　development　after　transforming　the　dynamics　of　each　quadrotor　into　a　new　form.　At　first,　an　intermediary　control　variable　is　introduced　to　achieve　the　formation　control,　where　some　auxiliary　systems　are　designed　in　the　presence　of　lacking　linear　velocity　measurements.　Then,　based　on　the　thrust　force　and　reference　angular　velocity　decoded　from　the　intermediary　control　variable,　the　torque　input　of　each　quadrotor　is　proposed　for　angular　velocity　tracking.　The　case　of　formation　control　with　a　virtual　leader　is　also　investigated,　where　at　least　one　quadrotor　has　the　information　of　the　leader.　The　asymptotic　stability　of　the　proposed　control　system　is　analyzed　by　Lyapunov-like　tools,　and　the　effectiveness　of　the　proposed　control　method　is　verified　by　simulation　studies.　The　simulation　results　show　that　the　proposed　method　can　guide　the　quadrotor　group　to　form　the　desired　formation　smoothly　without　linear　velocity　feedback,　which　has　great　potentials　for　the　UAV　group　to　execute　the　challenging　mission　in　hostile　environments.　©　2021,　ICROS,　KIEE　and　Springer.