Composite superstring model for hadrons. Theorem about absence of states with negative norms in the spectrum of physical states in this model.
Hadron dynamics is formulated in terms of interacting composite strings. Consistent composite string model with extended Virasoro superconformal symmetry is found. These composite strings carry flavour and chiral degrees of freedom on edging two-dimensional surfaces. Necessary correct description of string amplitudes without states of negative norms in the spectrum of physical states is reached when special supercurrent conditions are fulfilled.