Interactions between two chains consisted of micro-sized magnetic beads are experimentally investigated. Driven by a rotating field, three distinct modes of magnetic interactions are identified, referred to as chaining, locking and transit. The two chains gradually approach to form a longer chain in the chaining mode. The locking mode refers the chains undergo an interesting orbital-like circular motion, which mimics a binary star system. The chains could also evolve from locking to chaining in the transit mode. A necessary criterion for a locking mode is derived, which agrees excellently with the correspondent experiments.