The present invention discloses a detection circuit in the assembly process of an LCD panel. Through the testing pad collection and the switch collection, the signal line of each of the panel units connects to the corresponding testing signal pad of the testing pad collection respectively through the input terminal and the output terminal of the control switch of the switch collection, and the control terminal of the control switch electrically connects to the control signal pad in order to selectively apply an individual testing to one of the panel units. The present invention also provides a manufacturing method for an LCD panel. Accordingly, the present invention can simplify the detection circuit and reduce the load of the detection circuit.