The invention provides a forced commutation bridge circuit. A one-phase semi-bridge arm of the commutation bridge circuit comprises two thyristor strings which are connected in parallel, and each thyristor string comprises 2N thyristors which are connected in series, wherein N is at least equal to 1; the midpoints of the two thyristor strings are connected through a capacitor by which each thyristor string is divided into two symmetric segments of thyristor strings. Compared with the prior art, the forced commutation bridge circuit provided by the invention is suitable for traditional high-voltage direct-current power transmission, and not only can be used for realizing the reliable cutoff of the thyristors under a fault condition, but also can ensure that the capacitor is not used when a converter valve is normally used, so that no great number of harmonic waves are generated, and the service life of the capacitor is prolonged; moreover, the capacitor can be self-charged without an external power source.