The invention discloses an extremely-simple component steel plate for high-strength structures and a manufacture method thereof. The extremely-simple component steel plate mainly comprises the following chemical components in percentage by weight: 0.12-0.20% of C, 0.15-0.50% of Si, 1.30-1.80% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.020-0.050% of Al, 0.015-0.035% of Ti, 0.020-0.060% of Nb, 0.0015-0.0035% of B and the balance of Fe and inevitable impurities. The steel plate provided by the invention is simple in component, but the strength, tenacity, plasticity and other mechanical performance indexes of the steel plate are excellent, so that the steel plate is good in quality and stable and uniform in performance; the carbon equivalent is low, so that welding is easy; and the steel plate can be absolutely applied to manufacture of mechanical structural components which have high requirements on strength and tenacity.