The 30-year-old midfielder will end his two-and-a-half-year stint in Bologna to link up with Guangzhou's Italian coach Marcello Lippi.
Guangzhou won the Chinese Super League and AFC Champions League in a terrific season and have bolstered their squad with the addition of the experienced Diamanti.
A statement on the Italian club's website read: "Bologna announces that it has reached an agreement with Guangzhou Evergrande for the permanent transfer of Alessandro Diamanti."
The former Livorno, West Ham and Brescia player is excited to make the move to Asia.
"I am pleased to be able to start with my family this new adventure," Diamanti said.
"I thank the whole club and especially the city of Bologna, which has made me feel important on and off the field."
