I live on the fourth floor, and here comes a toad who can only climb the wall. What kind is this? Is it poisonous?

Judging from your picture, this is a tree frog without poison.

Tree frog, anurak tree frog family 1 genus, has a slender and flat body, long hind legs, large sucker and developed fingers and toes, which can be used for air gliding. Its main skeletal characteristics are the same as those of Ranidae.

Vertebral body is uneven or concave; The ends of fingers and toes swell into obvious suction cups, and there are edge grooves on the ventral edge of the suction cups. Generally, there is no transverse depression on the back of the sucker, and the ventral surface of the sucker is like a meat pad.