Embodiments of the present invention provide a method for determining a KPI degradation cause and an apparatus, which relate to the communications field, can reduce reporting overheads of a UE, ensure quality of an uplink service performed by the UE, decrease impact of reported measurement information on a network, and improve network problem processing efficiency. The method may include: receiving, by a first base station, a service message sent by a UE, where the service message carries first measurement information, the first measurement information is information about a service measurement performed by the UE on a first cell, and the first cell is served by the first base station; obtaining, by the first base station, the first measurement information according to the service message; generating, by the first base station, MNT measurement information according to the first measurement information; and sending, by the first base station, the MNT measurement information to an OSS, where the MNT measurement information is used by the OSS for determining the KPI degradation cause.