A mobile phone holder includes: a first coupling part having a first accommodating portion, a first clamping portion and a first pressing portion; a second coupling part having a second accommodating portion, a second clamping portion, a second pressing portion, and a sliding opening; and an extension spring. The first pressing portion penetrates into the second accommodating portion and penetrates out through the sliding opening. A clamping space is formed by the first and second clamping portions. A pressing space is formed by the first and second pressing portions. Both ends of the extension spring are fixed at the first and second accommodating portions. The first and second pressing portions are pressed toward each other such that the pressing space decreases and the clamping space increases. The first and second pressing portions are released, thereby due to a tensile force, the pressing space increases and the clamping space decreases.