Abstract: A motor casing of a ceiling fan has two pairs of lugs extending radially inward from the periphery thereof and the motor casing encloses the motor of the ceiling fan. A frame fixedly connected to a ceiling and has a flange to which two positioning devices are connected. Each positioning device has two support portions extending radially inward therefrom and each support portion has a slot. A resilient member connected to each support portion and is engaged between the two lugs corresponding to the positioning device so that the assembler can easily connect the motor casing and the frame without using bolts.