A protective cover is used for covering and fixing a mobile device selectively fixed to a fastener having a first or second female part. The protective cover includes an elastic protective-cover main body, a first rigid male part and a second rigid male part. The first and second rigid male parts to match first and second female parts of the fastener are selectively engaged with the elastic protective-cover main body. In addition, a protective cover kit is provided to include an elastic protective-cover main body, a rigid male part and a female-part carrier assembly. The female-part carrier assembly includes a universal female part and a female-part carrier. The universal female part, detachably connected with the female-part carrier, is universally used for detachably engaging the first or second connection part of the rigid male part. Thereupon, poor commonality between the male and female parts can be resolved.