The embodiment of the invention provides a software installation start type detection method and device and a user terminal. The software installation start type detection method comprises the following steps: responding to the software start operation, obtaining the storage path of a software installation package, finding out the software installation package and obtaining the software modification time recorded in the software installation package; obtaining the software modification time recorded in a storage framework of a user terminal operating system; judging the start type of the software according to the software modification time recorded in the software installation package and the software modification time recorded in the storage framework. The method and the device can achieve the effects of accurately judging the installation start type of the software and then preventing breakdown misjudgment caused by abnormal exit during software update installation.