The invention belongs to the technical field of display, and particularly relates to a flexible substrate, a display device and a method for attaching electronic devices on the flexible substrate. The flexible substrate comprises a base plate; the base plate comprises an attaching portion used for attaching of the electronic devices and an auxiliary attaching portion integrally formed with the attaching portion; the auxiliary attaching portion and the attaching portion are arranged back to back; and the attaching portion totally falls into an area of the auxiliary attaching portion in the orthographic projection direction. The flexible substrate has the advantages that since the auxiliary attaching portion is arranged next to the attaching portion for attaching of the electronic devices such as ICs (integrated circuits) or FPCs (flexible printed circuits), strength of the attaching portion can be enhanced by the aid of the auxiliary attaching portion when the electronic devices are attached to the attaching portion, attachment alignment precision and contact properties of the electronic devices are improved, further yield of flexible display devices is improved, and cost is low.