The invention relates to a 235MPa-grade LP steel plate and a production method thereof. An LP steel plate is a wedge-shaped steel plate, wherein one end of the LP steel plate is thin and the other endof the LP steel plate is thick; chemical components of the thin end of the LP steel plate are chemical components I, and chemical components of the thick end of the LP steel plate are chemical components II; the chemical components of the middle part of the LP steel plate are transmitted to the chemical components II from the chemical components I from the thin end to the thick end; and yield strength of the LP steel plate is 235-300 MPa, and impact power of the LP steel plate at a temperature being (-)20 DEG C is higher than or equal to 65 J. Two tanks of molten steel with different chemicalcomponents are adopted to pour continuously-cast steel billets, which have uniformly-changed chemical components in the longitudinal direction, and are directly rolled to produce the LP steel plate;the LP steel plate has the characteristic of being uniform and consistent in performance from the thin end to the thick end; and the LP steel plate is excellent in integral performance and is strong in applicability.