f = 1/(4 \[Theta]^2) (-c^2 + c (2 a + c) \[Theta] -
a (a + 2 c) \[Theta]^2 - (c k + p) (-2 a + c k +
p) \[Theta]^3 + ((-a + c k +
p)^2 \[Alpha]^2 \[Theta]^4)/(1 - \[Theta] + \[Alpha] (-1 +
2 \[Theta]))^2 - ((-a + c k +
p)^2 \[Alpha] \[Theta]^3 (-\[Theta] + \[Alpha] (-1 +
3 \[Theta])))/(\[Alpha] + \[Theta] -
2 \[Alpha] \[Theta])^2 + ((-1 + \[Alpha]) (-1 + \[Theta]) \
\[Theta] (a \[Alpha] \[Theta] +
c (-1 + \[Alpha] + \[Theta] -
2 \[Alpha] \[Theta]))^2)/(\[Alpha] (1 - \[Theta] + \[Alpha] \
(-1 + 2 \[Theta]))^2) + (\[Alpha]^2 \[Theta]^4 (-a \[Theta] +
a \[Alpha] (-1 + 3 \[Theta]) +
c (\[Alpha] + \[Theta] -
2 \[Alpha] \[Theta]))^2)/((\[Alpha] + \[Theta] -
3 \[Alpha] \[Theta])^2 (\[Alpha] + \[Theta] -
2 \[Alpha] \[Theta])^2))
Manipulate[
Plot[f, {\[Alpha], 0.5, 1}], {\[Theta], 0, 0.3}, {a, 3, 6}, {c, 1,
3}, {k, 0, 2}, {p, 0, 2}]

调一下θ的取值，改成0.001之类的就可以了

现在知道了，应该是，我的式子分母有可能为0，结果就跑不出来图像

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