In the estimation of Taiwan's real GDP during 1910-1950, Wu (l991) used a deflator series constructed from some wholesale price indices. This methodology is inconsistent with the recommendation given in the A System of National Accounts (1993). In this paper, we follow the recommended procedure and reestimate Taiwan agricultural production during 1902-52. The new results are significantly different from the original estimates especially in the 1930s and 1940s. From the mid-1930s to mid-1940s, Taiwan was under economic regulation, in 1945-1950, it suffered a hyperinflation. This paper investigates how economic regulation and hyperinflation will affect estimation of real production value.