A service monitoring method, wherein the method comprises: receiving, by a first detection node in a detection domain, a current data packet of a target service; adding, by the first detection node in the detection domain, detection indication information to the current data packet, to obtain a target data packet, wherein the detection indication information comprises a target phase category corresponding to the current data packet, the target phase category is used to indicate a target phase in at least one key phase in which the current data packet is located in the target service, and the detection indication information is used to indicate to detect the current data packet; and transmitting, by the first detection node in the detection domain, the target data packet to a next hop node, receiving, by a second detection node in the detection domain, the target data packet, detecting, by the second detection node in the detection domain, the target data packet based on the detection indication information, to determine a network key performance indicator KPI of the target data packet; generating, by the second detection node in the detection domain, an abnormal event notification if determining that the network KPI of the target data packet does not meet a network KPI corresponding to the target phase category, wherein the network KPI corresponding to the target phase category is a network KPI that corresponds to the target phase of the target service when a quality of experience QoE indicator meets a target ideal condition; and transmitting, by the second detection node in the detection domain, the abnormal event notification to a statistics collection node, wherein the method further comprises: obtaining, by the first detection node in the detection domain, a network key performance indicator KPI corresponding to the target phase category; and setting, by the first detection node in the detection domain, in the detection indication information, the network KPI corresponding to the target phase category, wherein the network KPI corresponding to the target phase category is a network KPI that corresponds to the target phase of the target service when a quality of experience QoE indicator meets a target ideal condition wherein the target service is a live video service, and the key phase is any one of a head-end collection phase, an initial buffering phase, a scenario switching phase, or a head rotation rendering phase. receiving, by a first detection node in a detection domain, a current data packet of a target service; adding, by the first detection node in the detection domain, detection indication information to the current data packet, to obtain a target data packet, wherein the detection indication information comprises a target phase category corresponding to the current data packet, the target phase category is used to indicate a target phase in at least one key phase in which the current data packet is located in the target service, and the detection indication information is used to indicate to detect the current data packet; and transmitting, by the first detection node in the detection domain, the target data packet to a next hop node, receiving, by a second detection node in the detection domain, the target data packet, detecting, by the second detection node in the detection domain, the target data packet based on the detection indication information, to determine a network key performance indicator KPI of the target data packet; generating, by the second detection node in the detection domain, an abnormal event notification if determining that the network KPI of the target data packet does not meet a network KPI corresponding to the target phase category, wherein the network KPI corresponding to the target phase category is a network KPI that corresponds to the target phase of the target service when a quality of experience QoE indicator meets a target ideal condition; and transmitting, by the second detection node in the detection domain, the abnormal event notification to a statistics collection node, wherein the method further comprises: obtaining, by the first detection node in the detection domain, a network key performance indicator KPI corresponding to the target phase category; and setting, by the first detection node in the detection domain, in the detection indication information, the network KPI corresponding to the target phase category, wherein the network KPI corresponding to the target phase category is a network KPI that corresponds to the target phase of the target service when a quality of experience QoE indicator meets a target ideal condition wherein the target service is a live video service, and the key phase is any one of a head-end collection phase, an initial buffering phase, a scenario switching phase, or a head rotation rendering phase. obtaining, by the first detection node in the detection domain, a network key performance indicator KPI corresponding to the target phase category; and setting, by the first detection node in the detection domain, in the detection indication information, the network KPI corresponding to the target phase category, wherein the network KPI corresponding to the target phase category is a network KPI that corresponds to the target phase of the target service when a quality of experience QoE indicator meets a target ideal condition wherein the target service is a live video service, and the key phase is any one of a head-end collection phase, an initial buffering phase, a scenario switching phase, or a head rotation rendering phase.