A hierarchical structure model is developed for anomalous scaling of the Lagrangian velocity structure functions in fully developed turbulence. This model is an extension of the Eulerian hierarchical structure model of She and Leveque [Phys. Rev. Lett. 72, 366 (1994)] to the Lagrangian velocity structure functions, where the straining and sweeping hypotheses are used to build up the relationship between the singular scalings of Lagrangian and Eulerian intermittent structures. The Lagrangian scaling exponents obtained from the straining hypothesis are in good agreement with the experimental results of the Bodenschatz group. [4,5]. The experiments found that strong intermittency exists in the Lagrangian VSFs [6], which leads to the large deviations of the Lagrangian scaling exponents from the K41 theory [7,8]. The deviations call for a theoretical description. An exact expression for Lagrangian scaling exponents deduced from the Navier-Stokes equations is still unavailable. Hence, it is necessary to develop a phenomenological model for the correction to Kolmogorov's prediction based on the physics of the Navier-Stokes equations. In this Rapid Communication, we will develop such a simple model to analytically predict the Lagrangian scaling exponents.Since both Lagrangian and Eulerian statistical quantities are determined by the same turbulent flows, there must exist a relationship between these quantities. In the multifractal formulism, a multifractal dimension spectrum uniquely determines the scaling exponents and vice versa. Borgas [9] formulates a relationship between the Eulerian and Lagrangian multifractal dimension spectra. The relationship can be used to calculate the Lagrangian multifractal dimension spectra from the Eulerian ones and yield the Lagrangian scaling exponents. The Lagrangian scaling exponents thus obtained are in good agreement with the experimental measurements for lower orders but less good agreement with them for high orders [7]. Recently, Beck [10] has developed a superstatistical model for Lagrangian scaling exponents, and Zybin et al. [11] have calculated the Lagrangian scaling exponents using the vortex filaments. Using the multifractal formalism, the She and Leveque (SL) model [12] introduces a Eulerian hierarchical structure to describe the Eulerian scaling exponents with its successes. The present work introduces a Lagrangian hierarchy structure to develop a simple model for the Lagrangian scaling exponents without any adjustable parameters.* Author to whom all correspondence should be addressed: hgw@lnm.imech.ac.cn or guoweihe@yahoo.comWe consider the Lagrangian VSFs of positive integer order p:where v i (i = x,y,z) are the velocity components along a single particle path and the repeated indices imply a summation. The ensemble averages are defined as the summation of all samples of particle trajectories. Due to the stationarity and homogeneity in fully developed turbulence, the Lagrangian VSFs are only dependent on time increment τ . The K41 theory implies that the Lagrangian VSF...