The invention discloses a construction method for a bored pile of a subway station enclosure structure of upper-soft lower-hard ground. The method includes the steps that firstly, measurement and paying-off are conducted, wherein measurement and paying-off are carried out at a pile position of the bored pile to be constructed, and the bored pile to be constructed is a cast-in-place pile constructed and formed in the upper-soft lower-hard ground; secondly, a steel casing is buried, wherein the steel casing is buried in the soft ground where the bored pile to be constructed is located; thirdly, drilling construction of pile holes is conducted; fourthly, a steel rib frame is laid down; fifthly, concrete pouring construction is conducted; sixthly, the steel casing is detached; seventhly, the bored pile is formed. Drilling construction of the pile holes includes the steps that 301, drilling construction is conducted on an upper pipe hole section and 302, drilling construction is conducted on a lower pile hole section, wherein the lower pile hole section is subjected to drilling construction by being divided into multiple pile hole section bodies from top to bottom, and when any hole section body is subjected to drilling construction, drilling for cores and secondary overcoring are conducted. The method is simple, design is reasonable, construction is easy and convenient, drilling difficulty of the pile holes is low, the use effect is good, and the bored pile construction process of the upper-soft lower-hard ground can be easily, conveniently and quickly completed.