Dynamics of nano-sized colloidal particles in a swollen lyotropic lamellar phase of a nonionic surfactant has been studied by three methods of inicrorheology. By electrophoretic microrheology (EPM), we find two relaxation processes respectively relating to the fluctuation of membranes and topological defects in lamellar structure. By direct tracking of particles under a microscope and manipulating them with an optical tweezers, we obtained detailed information on diffusion. of a particle at low frequencies. We observed the jump-trap motion of a particle and the non-Newtonian rheological behavior at low frequencies.