用`pos=...`指定`path`上的`node`位置 ```tex \documentclass[border=1cm]{standalone} \usepackage{tikz} \usepackage{amsmath} \usetikzlibrary{shapes.geometric,arrows,backgrounds} \tikzstyle{startstop} = [rectangle, rounded corners, minimum width=1cm, minimum height=1cm, text centered, draw=black, fill=red!30] \tikzstyle{arrow} = [thick,->,>=stealth] \begin{document} \begin{tikzpicture}[node distance=3cm] % adding nodes \node (S) [startstop] {$S$}; \node (E) [startstop, right of=S] {$E$}; \node (I) [startstop, right of=E] {$I$}; \node (H) [startstop, right of=I] {$H$}; \node (F) [startstop, above of=E]{$F$}; \node (A) [startstop, below of=E] {$A$}; \node (P) [startstop, below of=I] {$P$}; \node (R) [startstop, below of=H] {$R$}; % adding arrows \draw [arrow] (S) -- node[anchor=south] {$\beta,\beta',\beta l$} (E); \draw [arrow] (E) -- node[anchor=east] {$\kappa(1-\rho_1-\rho_2)$} (A); \draw [arrow] (E) -- node[above, pos=.25] {$\kappa\rho_1$} (I); \draw [arrow] (E) -- node[below left, inner sep=1pt, pos=.4] {$\kappa\rho_2$} (P); \draw [arrow] (I) -- node[anchor=north] {$\delta_i$} (F); \draw [arrow] (I) -- node[anchor=south] {$\gamma_a$} (H); \draw [arrow] (I) -- node[below left, pos=.3, inner sep=2pt] {$\gamma_i$} (R); \draw [arrow] (H) -- node[anchor=south] {$\gamma_r$} (F); \draw [arrow] (H) -- node[anchor=west] {$\delta_h$} (R); \draw [arrow] (P) -- node[above right, pos=.3, inner sep=2pt] {$\delta_p$} (F); \draw [arrow] (P) -- node[below right, pos=.25, inner sep=2pt] {$\gamma_a$} (H); \draw [arrow] (P) -- node[anchor=north] {$\gamma_i$} (R); %\draw [arrow] (dec1) -- node[anchor=east] {是} (pro6); %\draw [arrow] (dec1) -- node[anchor=south] {否}(pro5); \end{tikzpicture} \end{document} ```