Sinusoidal cracks are often observed in internally pressurized tubes or thermally quenched glasses. In this study, stress intensity factors were analyzed for a single sinusoidal crack or periodically situated sinusoidal cracks in an infinite plate using the method of continuously distributed dislocations model. As the applied stress at infinity, not only the uniaxial tension but also the biaxial tension was considered. This paper shows the calculated stress intensity factors ratio K_<11>/K_1 and the direction of the crack propagation is investigated. As the result, it has been clarified that when periodically situated sinusoidal cracks are under biaxial tension, they will be likely to propagate to the direction which increases their amplitudes.