Abstract: The vibration modes of a finite periodical string-ball chain are studied with both experimental and calculation methods. The vibration spectrum of the system appears band structure and the surface states could be observed in band gap. The eigenfrequencies of the surface states are measured and calculated for different distances τ from the start of the chain to the first ball. A brief discussion is given for the observations and calculations.

Key words: periodical system, string vibration, vibration modes, surface state