Si Chi Ko and his "painting with a camera" have been praised by the likes of Nobel-prize-winning author (and painter) Gao Xingjian: "Photography as an art has such a short history in China. I don't know of anyone who has advanced it further than Si Chi Ko."
Ko's deeply humanistic early work moved viewers with its black-and-white depictions of socially realistic themes. His middle-period commercial work was deemed striking even in New York and laid the foundation for his reputation as a master photographer. In 1979, he threw off the fetters of fame and fortune and began exploring his inner vision. He made use of extremely high contrast in these works, producing incomparably clean and pure images that were endlessly expressive in their silence. In this late period, his work achieved a level few others could rival.
The author Sung Pei has suggested that Ko's photographs represent the interaction and coexistence of "the unresolved" and "the quietly settled." Director Huang Ming-chuan has argued that they are the ultimate expression of "omnipresent isolation." Ko himself says that viewing the world with the eyes boxes it into a kind of frame; whereas experiencing it with the heart opens it up. Exploring the chan (Zen) aesthetic of Ko's work with the heart, then examining it with the eyes is like viewing two different worlds.