This　work　investigates　the　time-varying　formation　tracking　problems　for　linear　multi-agent　systems　with　a　leader　of　bounded　unknown　control　input　in　the　presence　of　external　disturbances　on　directed　graphs.　To　eliminate　the　external　disturbances,　an　extended　state　observer　is　constructed　for　each　agent　first.　Then,　a　distributed　time-varying　formation　tracking　protocol　is　designed　by　utilizing　the　estimated　information,　which　does　not　require　the　global　communication　graph　information.　The　multi-agent　system　is　shown　to　asymptotically　track　the　leader　with　time-varying　formations　and　meanwhile　reject　the　disturbance　if　the　expected　formation　satisfies　the　feasible　condition　by　Lyapunov　stability　analysis.　Finally,　a　simulation　example　of　switching　formation　is　provided　to　verify　the　effectiveness　of　the　proposed　approach.　©　2022　Technical　Committee　on　Control　Theory,　Chinese　Association　of　Automation.