A method for determining a forwarding path, applied to a communications network, comprising: obtaining, by a control device, a first-forwarding-path computation request, wherein the first-forwarding-path computation request instructs to compute a first forwarding path that is from a source node to a destination node and that satisfies a necessary constraint; when at least two forwarding paths that satisfy the necessary constraint are obtained through computing, obtaining, by the control device based on a mapping relationship between path computation reference constraints and priorities, a path computation reference constraint having a highest priority, wherein the mapping relationship between path computation reference constraints and priorities comprises N path computation reference constraints C i and N priorities P i, P i is in a one-to-one correspondence with C i, i is a positive integer greater than or equal to 1 and less than or equal to N, and N is a positive integer greater than or equal to 2, and further comprises N path-computation-reference-constraint enable switches E i, wherein E i is in a one-to-one correspondence with C i, E i is used to indicate whether C i corresponding to E i is enabled, and if E i is in an enabled state, C i corresponding to E i is a path computation reference constraint that can be used, and wherein the obtaining, by the control device based on a mapping relationship between path computation reference constraints and priorities, a path computation reference constraint having a highest priority comprises: selecting, by the control device, at least one C i in an E enabled state based on E i, and then selecting, by the control device, from the at least one C i in an E enabled state based on P i, C i corresponding to a highest priority P i; and determining, by the control device, based on the path computation reference constraint having the highest priority and from the at least two forwarding paths that satisfy the necessary constraint, at least one forwarding path that satisfies the path computation reference constraint having the highest priority. obtaining, by a control device, a first-forwarding-path computation request, wherein the first-forwarding-path computation request instructs to compute a first forwarding path that is from a source node to a destination node and that satisfies a necessary constraint; when at least two forwarding paths that satisfy the necessary constraint are obtained through computing, obtaining, by the control device based on a mapping relationship between path computation reference constraints and priorities, a path computation reference constraint having a highest priority, wherein the mapping relationship between path computation reference constraints and priorities comprises N path computation reference constraints C i and N priorities P i, P i is in a one-to-one correspondence with C i, i is a positive integer greater than or equal to 1 and less than or equal to N, and N is a positive integer greater than or equal to 2, and further comprises N path-computation-reference-constraint enable switches E i, wherein E i is in a one-to-one correspondence with C i, E i is used to indicate whether C i corresponding to E i is enabled, and if E i is in an enabled state, C i corresponding to E i is a path computation reference constraint that can be used, and wherein the obtaining, by the control device based on a mapping relationship between path computation reference constraints and priorities, a path computation reference constraint having a highest priority comprises: selecting, by the control device, at least one C i in an E enabled state based on E i, and then selecting, by the control device, from the at least one C i in an E enabled state based on P i, C i corresponding to a highest priority P i; and determining, by the control device, based on the path computation reference constraint having the highest priority and from the at least two forwarding paths that satisfy the necessary constraint, at least one forwarding path that satisfies the path computation reference constraint having the highest priority.